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package org.graalvm.util;

import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;

Wrapper class for annotation access that defends against https://bugs.openjdk.java.net/browse/JDK-7183985: when an annotation declares a Class array parameter and one of the referenced classes is not present on the classpath parsing the annotations will result in an ArrayStoreException instead of caching of a TypeNotPresentExceptionProxy. This is a problem in JDK8 but was fixed in JDK11+. This wrapper class also defends against incomplete class path issues. If the element for which annotations are queried is a JMVCI value, i.e., a HotSpotResolvedJavaField, or HotSpotResolvedJavaMethod, the annotations are read via HotSpotJDKReflection using the getFieldAnnotation()/getMethodAnnotation() methods which first construct the field/method object via CompilerToVM.asReflectionField()/CompilerToVM.asReflectionExecutable() which eagerly try to resolve the types referenced in the element signature. If a field declared type or a method return type is missing then JVMCI throws a NoClassDefFoundError.
/** * Wrapper class for annotation access that defends against * https://bugs.openjdk.java.net/browse/JDK-7183985: when an annotation declares a Class<?> array * parameter and one of the referenced classes is not present on the classpath parsing the * annotations will result in an ArrayStoreException instead of caching of a * TypeNotPresentExceptionProxy. This is a problem in JDK8 but was fixed in JDK11+. This wrapper * class also defends against incomplete class path issues. If the element for which annotations are * queried is a JMVCI value, i.e., a HotSpotResolvedJavaField, or HotSpotResolvedJavaMethod, the * annotations are read via HotSpotJDKReflection using the * getFieldAnnotation()/getMethodAnnotation() methods which first construct the field/method object * via CompilerToVM.asReflectionField()/CompilerToVM.asReflectionExecutable() which eagerly try to * resolve the types referenced in the element signature. If a field declared type or a method * return type is missing then JVMCI throws a NoClassDefFoundError. */
public final class GuardedAnnotationAccess { public static boolean isAnnotationPresent(AnnotatedElement element, Class<? extends Annotation> annotationClass) { return getAnnotation(element, annotationClass) != null; } public static <T extends Annotation> T getAnnotation(AnnotatedElement element, Class<T> annotationType) { try { return element.getAnnotation(annotationType); } catch (ArrayStoreException | NoClassDefFoundError e) { /* * Returning null essentially means that the element doesn't declare the annotationType, * but we cannot know that since the annotation parsing failed. However, this allows us * to defend against crashing the image builder if the above JDK bug is encountered in * user code or if the user code references types missing from the classpath. */ return null; } } public static Annotation[] getAnnotations(AnnotatedElement element) { try { return element.getAnnotations(); } catch (ArrayStoreException | NoClassDefFoundError e) { /* * Returning an empty array essentially means that the element doesn't declare any * annotations, but we know that it is not true since the reason the annotation parsing * failed is because some annotation referenced a missing class. However, this allows us * to defend against crashing the image builder if the above JDK bug is encountered in * user code or if the user code references types missing from the classpath. */ return new Annotation[0]; } } public static <T extends Annotation> T getDeclaredAnnotation(AnnotatedElement element, Class<T> annotationType) { try { return element.getDeclaredAnnotation(annotationType); } catch (ArrayStoreException | NoClassDefFoundError e) { /* * Returning null essentially means that the element doesn't declare the annotationType, * but we cannot know that since the annotation parsing failed. However, this allows us * to defend against crashing the image builder if the above JDK bug is encountered in * user code or if the user code references types missing from the classpath. */ return null; } } public static Annotation[] getDeclaredAnnotations(AnnotatedElement element) { try { return element.getDeclaredAnnotations(); } catch (ArrayStoreException | NoClassDefFoundError e) { /* * Returning an empty array essentially means that the element doesn't declare any * annotations, but we know that it is not true since the reason the annotation parsing * failed is because it at least one annotation referenced a missing class. However, * this allows us to defend against crashing the image builder if the above JDK bug is * encountered in user code or if the user code references types missing from the * classpath. */ return new Annotation[0]; } } }